The National Symphony Orchestra is performing a new overture to businesses this year, hoping finally to conduct a rhapsody in black.

The symphony, celebrating its 50th anniversary, has started a fund-raising campaign that for the first time directs a concerted effort at getting local business support initially and later expanding the push to corporations nationwide. The organization hopes this can rid the orchestra of the red-ink figures that have plagued it.

"The nation's capital deserves a world-class orchestra, and it merits the confidence and support of business," said Robert Tardio, chairman of Suburban Bancorporation of Maryland and cochairman of the symphony's committee on local business, in describing the approach being taken to area executives. "Anything that enhances the cultural quality of the area helps in attracting and keeping businesses" in the city, he said.

The goal of this year's campaign is to raise a total of $5.5 million from individuals and businesses by the end of September, enough to take the symphony out of debt for the first time in years, said campaign director Dan Keith Ray, a consultant from Third Sector Project, a nonprofit organization that helps other nonprofit organizations. After this phase of the drive, $11 million in new endowments will be sought to give the symphony a future "cushion" to keep it out of debt, he said.

So far this year, the symphony has received $3.4 million, including a $1 million federal grant, and the campaign now is looking to some 6,000 local companies to take that figure beyond $4 million by midsummer.

The local-business phase of the campaign began with a letter to executives that went out last week, timed to coincide with a general media blitz started this month and continuing to June 15. Volunteers from the business community will follow up by contacting executives in their industry.

Local firms already have contributed time and talent to making the symphony's management and marketing more businesslike, Ray said. For example: The Mars candy company did a management study and helped the symphony find its new executive director; accountants Coopers and Lybrand did a 5- to 10-year financial projection; IBM loaned the symphony an executive who helped update and consolidate its computer system; Booz-Allen & Hamilton prepared a marketing analysis of the current audience to help see how to target potential subscribers, and Geico Corp. is helping prepare a follow-up appeal for the summer months, he said. And, Potomac Electric Power Co. loaned an executive to help the symphony realign its image with a new logo and a new ad campaign with the slogan.

Clearly the Pepco representative looks forward to a warmer reception for the symphony's concerts than greets the latest round of utility rate increases. ". . . Bravos that spring unbidden from your throat," one ad promises. Others envision " . . . champagne and chandeliers . . . the magic of Mozart . . . a swirling mass of color . . . rubbing elbows with connoisseurs." Each is capped with a slogan: "You owe it to yourself to get in on the act."

Local radio and television stations are contributing time for 30- and 60-second spots during the six-week media blitz, and TV station WDVM is in the middle of a special tribute week for the symphony, to end with a half-hour documentary Saturday night. The orchestra is running full-page newspaper ads.

The media campaign is aimed at a mass audience of potential theater-goers, part of a goal to increase subscriptions by 10 percent this year.

The approach to businesses retains an appeal to aesthetics but adds an element of practicality. Included with the leters to executives that went out last week are "prospectuses" for different levels of "investments" from $1,000 to $10,000.

A $10,000 commitment will be rewarded with concert tickets for the sponsor and 100 friends, as well as "membership in the NSO's most exclusive club" and an open invitation to visit backstage with Maestro Mstislav Rostropovich, guest artists and orchestra. For $2,500 the sponsor gets concert seats for 25 as well as the open invitation to go back stage. For $1,000, a contributor doesn't get a concert but still can chat with the maestro.

From strictly a business standpoint, the symphony in the past would have to be considered a loser. With a budget of about $8 million a year, its deficit was projected to approach $2 million for this fiscal year. Most of the expenses -- $5.7 million -- is for musicians' salaries, royalty payments and other music-related costs. Fund-raising takes another $1 million, or 13 percent of the budget; advertising $666,000, or 8 percent; and rent paid to the Kennedy Center is $563,000 a year.

Ticket sales bring in about $3 million, and Congress last year approved a one-time grant of $1 million, which the symphony is using in its fund-raising efforts. Most of the rest of the funds for the symphony must come from private donations and endowments.

And although improved management and marketing can help the symphony's balance sheet, Ray says that even if all 27,000 symphony seats were sold on all four concert nights a week, the symphony could not break even with ticket sales alone. But this inability to be self-sustaining is typical of any arts organization, he adds.

Symphony Board Chairman Leonard Silverstein of Silverstein and Mullens, a law firm, expresses the problem in terms familiar to corporate executives: "The symphony is a labor-intensive organization. You can't increase its productivity by automating," he explains.

What can be done is to make local businesses recognize the symphony as their key cultural obligation in the capital city; Silverstein says. It's just as much a symbol of the city's importance as any other, more visible attractions, he says.